Boat trailers, utility trailers and camper trailers around Flathead Lake spend a lot more time parked than they do on the road, and that changes what actually wears them out. A trailer tire rarely fails from too many miles. It fails from age, and a trailer that only comes out a handful of times a season is exactly the kind of tire that ages without anyone noticing.
Why Trailer Tires Age Differently
A vehicle tire wears mostly from mileage, tread wearing down through actual driving. A trailer tire that sits in a driveway or under a cover most of the year barely accumulates mileage at all, but the rubber still ages the same way any rubber does, breaking down slowly from UV exposure, temperature swings, and just time passing. That means a trailer tire can have plenty of tread depth left and still be unsafe, because the structure underneath has degraded even though the surface looks fine.
Check the Sidewalls First
Before anything else, look closely at the sidewalls. Cracking, sometimes fine hairline cracks that are easy to miss at a glance, is the clearest sign of age-related degradation. Run a hand over the sidewall too, not just a visual check, since some cracking is easier to feel than see. If you find noticeable cracking, that tire is a candidate for replacement regardless of how much tread is left on it.
Know Roughly How Old the Tires Are
Trailer tires have a manufacture date coded into the sidewall, and it's worth knowing roughly how old yours are if you don't already. A lot of guidance around trailer tires suggests replacement somewhere in the five to seven year range regardless of mileage, purely because of how rubber ages. If you don't know how old your trailer's tires are and can't find the date code, that uncertainty alone is a reason to have them checked before a long haul.
Check Pressure, Even After a Long Sit
Tires lose air slowly over time even without a puncture or leak, and a trailer that's been parked since last fall can be meaningfully underinflated by the time spring rolls around. Underinflation on a loaded trailer, hauling a boat down Highway 35 toward Bigfork or out toward the Somers marina, generates more heat in the tire than it's built to handle, which is a common contributor to trailer tire blowouts. Check pressure before every season's first real haul, not just when something looks obviously wrong.
Don't Forget the Spare
If your trailer carries a spare, it's easy to assume it's fine simply because it's never been used. A spare ages the same way the tires actually on the trailer do, and an unused spare that's five or six years old isn't automatically more reliable than the ones that see regular use. Give it the same sidewall and pressure check.
Load Matters More Than It Does on a Car
A trailer tire under a loaded boat or camper works harder than a passenger vehicle tire ever does relative to its size. That makes the margin for error smaller. A trailer tire that's borderline on age or pressure and gets away with it unloaded can fail under the added stress of a real load heading down the highway.
What Flathead Mobile Tire Does
We check, mount, and replace trailer tires right at your property, whether that's a driveway in Bigfork or a storage lot near Somers. See our trailer tires page, call for pricing since load range and trailer size vary. If a road trip turns into a flat anyway, our flat tire repair covers that too. We serve Bigfork and Somers along with the rest of the valley.
Trailer been sitting all winter? Book mobile service and we'll check it before it goes back on the road.
